/***************************************************************************/
/*                                                                         */
/*  ttinterp.h                                                             */
/*                                                                         */
/*    TrueType bytecode interpreter (specification).                       */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007 by             */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#ifndef __TTINTERP_H__
#define __TTINTERP_H__

#include <ft2build.h>
#include "ttobjs.h"


FT_BEGIN_HEADER


#ifndef TT_CONFIG_OPTION_STATIC_INTERPRETER /* indirect implementation */

    #define EXEC_OP_ TT_ExecContext exc,
    #define EXEC_OP TT_ExecContext exc
    #define EXEC_ARG_ exc,
    #define EXEC_ARG exc

#else                                       /* static implementation */

    #define EXEC_OP_ /* void */
    #define EXEC_OP /* void */
    #define EXEC_ARG_ /* void */
    #define EXEC_ARG /* void */

#endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */


/*************************************************************************/
/*                                                                       */
/* Rounding mode constants.                                              */
/*                                                                       */
#define TT_Round_Off 5
#define TT_Round_To_Half_Grid 0
#define TT_Round_To_Grid 1
#define TT_Round_To_Double_Grid 2
#define TT_Round_Up_To_Grid 4
#define TT_Round_Down_To_Grid 3
#define TT_Round_Super 6
#define TT_Round_Super_45 7


/*************************************************************************/
/*                                                                       */
/* Function types used by the interpreter, depending on various modes    */
/* (e.g. the rounding mode, whether to render a vertical or horizontal   */
/* line etc).                                                            */
/*                                                                       */
/*************************************************************************/

/* Rounding function */
typedef FT_F26Dot6
(*TT_Round_Func)(EXEC_OP_ FT_F26Dot6 distance,
                 FT_F26Dot6 compensation);

/* Point displacement along the freedom vector routine */
typedef void
(*TT_Move_Func)(EXEC_OP_ TT_GlyphZone zone,
                FT_UShort point,
                FT_F26Dot6 distance);

/* Distance projection along one of the projection vectors */
typedef FT_F26Dot6
(*TT_Project_Func)(EXEC_OP_ FT_Pos dx,
                   FT_Pos dy);

/* reading a cvt value.  Take care of non-square pixels if necessary */
typedef FT_F26Dot6
(*TT_Get_CVT_Func)(EXEC_OP_ FT_ULong idx);

/* setting or moving a cvt value.  Take care of non-square pixels  */
/* if necessary                                                    */
typedef void
(*TT_Set_CVT_Func)(EXEC_OP_ FT_ULong idx,
                   FT_F26Dot6 value);


/*************************************************************************/
/*                                                                       */
/* This structure defines a call record, used to manage function calls.  */
/*                                                                       */
typedef struct  TT_CallRec_
{
    FT_Int Caller_Range;
    FT_Long Caller_IP;
    FT_Long Cur_Count;
    FT_Long Cur_Restart;

} TT_CallRec, * TT_CallStack;


/*************************************************************************/
/*                                                                       */
/* The main structure for the interpreter which collects all necessary   */
/* variables and states.                                                 */
/*                                                                       */
typedef struct  TT_ExecContextRec_
{
    TT_Face face;
    TT_Size size;
    FT_Memory memory;

    /* instructions state */

    FT_Error error;                /* last execution error */

    FT_Long top;                   /* top of exec. stack   */

    FT_UInt stackSize;             /* size of exec. stack  */
    FT_Long* stack;                /* current exec. stack  */

    FT_Long args;
    FT_UInt new_top;               /* new top after exec.  */

    TT_GlyphZoneRec zp0,           /* zone records */
                    zp1,
                    zp2,
                    pts,
                    twilight;

    FT_Size_Metrics metrics;
    TT_Size_Metrics tt_metrics;    /* size metrics */

    TT_GraphicsState GS;           /* current graphics state */

    FT_Int curRange;              /* current code range number   */
    FT_Byte* code;                /* current code range          */
    FT_Long IP;                   /* current instruction pointer */
    FT_Long codeSize;             /* size of current range       */

    FT_Byte opcode;               /* current opcode              */
    FT_Int length;                /* length of current opcode    */

    FT_Bool step_ins;             /* true if the interpreter must */
                                  /* increment IP after ins. exec */
    FT_Long cvtSize;
    FT_Long* cvt;

    FT_UInt glyphSize;            /* glyph instructions buffer size */
    FT_Byte* glyphIns;            /* glyph instructions buffer */

    FT_UInt numFDefs;             /* number of function defs         */
    FT_UInt maxFDefs;             /* maximum number of function defs */
    TT_DefArray FDefs;            /* table of FDefs entries          */

    FT_UInt numIDefs;             /* number of instruction defs */
    FT_UInt maxIDefs;             /* maximum number of ins defs */
    TT_DefArray IDefs;            /* table of IDefs entries     */

    FT_UInt maxFunc;              /* maximum function index     */
    FT_UInt maxIns;               /* maximum instruction index  */

    FT_Int callTop,                /* top of call stack during execution */
           callSize;               /* size of call stack */
    TT_CallStack callStack;        /* call stack */

    FT_UShort maxPoints;             /* capacity of this context's `pts' */
    FT_Short maxContours;            /* record, expressed in points and  */
                                     /* contours.                        */

    TT_CodeRangeTable codeRangeTable;   /* table of valid code ranges */
                                        /* useful for the debugger   */

    FT_UShort storeSize;           /* size of current storage */
    FT_Long* storage;              /* storage area            */

    FT_F26Dot6 period;             /* values used for the */
    FT_F26Dot6 phase;              /* `SuperRounding'     */
    FT_F26Dot6 threshold;

    #if 0
    /* this seems to be unused */
    FT_Int cur_ppem;               /* ppem along the current proj vector */
    #endif

    FT_Bool instruction_trap;            /* If `True', the interpreter will */
                                         /* exit after each instruction     */

    TT_GraphicsState default_GS;         /* graphics state resulting from   */
                                         /* the prep program                */
    FT_Bool is_composite;                /* true if the glyph is composite  */
    FT_Bool pedantic_hinting;            /* true if pedantic interpretation */

    /* latest interpreter additions */

    FT_Long F_dot_P;               /* dot product of freedom and projection */
                                   /* vectors                               */
    TT_Round_Func func_round;      /* current rounding function             */

    TT_Project_Func func_project,      /* current projection function */
                    func_dualproj,     /* current dual proj. function */
                    func_freeProj;     /* current freedom proj. func  */

    TT_Move_Func func_move;            /* current point move function */
    TT_Move_Func func_move_orig;       /* move original position function */

    TT_Get_CVT_Func func_read_cvt;     /* read a cvt entry              */
    TT_Set_CVT_Func func_write_cvt;    /* write a cvt entry (in pixels) */
    TT_Set_CVT_Func func_move_cvt;     /* incr a cvt entry (in pixels)  */

    FT_Bool grayscale;                 /* are we hinting for grayscale? */

} TT_ExecContextRec;


extern const TT_GraphicsState tt_default_graphics_state;


FT_LOCAL(FT_Error)
TT_Goto_CodeRange(TT_ExecContext exec,
                  FT_Int range,
                  FT_Long IP);

FT_LOCAL(FT_Error)
TT_Set_CodeRange(TT_ExecContext exec,
                 FT_Int range,
                 void* base,
                 FT_Long length);

FT_LOCAL(FT_Error)
TT_Clear_CodeRange(TT_ExecContext exec,
                   FT_Int range);


/*************************************************************************/
/*                                                                       */
/* <Function>                                                            */
/*    TT_New_Context                                                     */
/*                                                                       */
/* <Description>                                                         */
/*    Queries the face context for a given font.  Note that there is     */
/*    now a _single_ execution context in the TrueType driver which is   */
/*    shared among faces.                                                */
/*                                                                       */
/* <Input>                                                               */
/*    face :: A handle to the source face object.                        */
/*                                                                       */
/* <Return>                                                              */
/*    A handle to the execution context.  Initialized for `face'.        */
/*                                                                       */
/* <Note>                                                                */
/*    Only the glyph loader and debugger should call this function.      */
/*                                                                       */
FT_EXPORT(TT_ExecContext)
TT_New_Context(TT_Driver driver);

FT_LOCAL(FT_Error)
TT_Done_Context(TT_ExecContext exec);

FT_LOCAL(FT_Error)
TT_Load_Context(TT_ExecContext exec,
                TT_Face face,
                TT_Size size);

FT_LOCAL(FT_Error)
TT_Save_Context(TT_ExecContext exec,
                TT_Size ins);

FT_LOCAL(FT_Error)
TT_Run_Context(TT_ExecContext exec,
               FT_Bool debug);


/*************************************************************************/
/*                                                                       */
/* <Function>                                                            */
/*    TT_RunIns                                                          */
/*                                                                       */
/* <Description>                                                         */
/*    Executes one or more instruction in the execution context.  This   */
/*    is the main function of the TrueType opcode interpreter.           */
/*                                                                       */
/* <Input>                                                               */
/*    exec :: A handle to the target execution context.                  */
/*                                                                       */
/* <Return>                                                              */
/*    FreeType error code.  0 means success.                             */
/*                                                                       */
/* <Note>                                                                */
/*    Only the object manager and debugger should call this function.    */
/*                                                                       */
/*    This function is publicly exported because it is directly          */
/*    invoked by the TrueType debugger.                                  */
/*                                                                       */
FT_EXPORT(FT_Error)
TT_RunIns(TT_ExecContext exec);


FT_END_HEADER

#endif /* __TTINTERP_H__ */


/* END */